Method for treating high-zinc iron-containing slime through utilizing rotary kiln

Abstract

The invention relates to a method for treating high-zinc iron-containing slime through utilizing a rotary kiln. The method comprises the steps that blast furnace gas ash and converter OG mud are mixed and pelletized; wet pellets are dried and preheated, and a drying and preheating heat source is hot air generated by high-temperature flue gas of the rotary kiln after passing through a high-low temperature composite air heat exchanger; a pea coal spray gun, a carbon residue spray gun and an ore grain spray gun are arranged at a kiln head of the rotary kiln, and high-volatile matter coal, residual carbon and high-grade iron ore are sprayed into the kiln; the dried pellets are fed into the rotary kiln, and high-temperature metallized pellets are obtained after the dried pellets are subjected to direct reduction and high-temperature solidification in the rotary kiln; after being cooled to the normal temperature, materials like the metallized pellets and excess carbon residue are subjected to magnetic separation, and metallized pellets are obtained; and large-particle dust is removed from the high-temperature flue gas of the rotary kiln, the high-temperature flue gas enters the high-low temperature composite air heat exchanger to be cooled, the cooled flue gas enters a bag-type dust collector, and zinc oxide powder is recycled. According to the method, the high-zinc iron-containing slime generated by iron and steel enterprises is efficiently utilized, and environmental pollution caused by stacking of the high-zinc iron-containing slime is solved.

Description

technical field [0001] The invention relates to the technical field of metallurgy and mineral engineering, and relates to a process for producing metallized charge and recovering zinc oxide powder from high-zinc and iron-containing dust in iron and steel enterprises. Background technique [0002] Iron-containing dust is the solid waste with the most types and the most complex components in the iron and steel industry. The total production volume accounts for about 5-6% of the iron and steel production, and it is the third largest solid waste after blast furnace slag and steel slag. The iron-containing dust generated in the steel production process mainly includes: sintering dust, pellet dust, blast furnace gas dust, converter OG mud, steelmaking dust, casthouse dust, etc. The main component of iron-containing dust sludge is iron, and its iron content is generally TFe30-65%, and it also contains certain harmful elements such as Zn, K, Na, etc. Among them, the Zn content of bl...

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Problems solved by technology

[0004] At present, there is a process of using a rotary kiln to treat high-zinc and iron-containing dust, but there are problems such as low ZnO content in the collected zinc ash, low dezincification rate, low metallization rate of the reduced material, and low production capacity of the rotary kiln.

At present, the rotary kiln process for processing high-zinc and iron-containing dust sludge does not make pellets, so a large amount of dust is generated during the rotation of the rotary kiln, and the dust enters the dust removal system with the flue gas, and enters the zinc ash after bag dust removal, making the collected zinc ash ZnO As no measures have been taken to strengthen the reducing atmosphere in the kiln, the reducing atmosphere is weak in the middle and later stages of high-temperature reduction, and the reduction reaction speed decreases or even stagnates, resulting in low metallization rate of the reduced material and zinc content in the reduced material Still high (about 1%), low dezincification rate, low production capacity of rotary kiln and other problems

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